Passivation process

ABSTRACT

A passivation process for decreasing the poisonous effects from contamination by metals, such as vanadium, iron, nickel or copper that can occur during a catalytic conversion of a hydrocarbon feedstock containing such metals is disclosed. The process employs compositions of organic or aqueous media containing one or more, at least partially soluble species of silicon, alone or in combination with phosphorus and/or aluminum-containing materials or species.

BACKGROUND OF THE INVENTION

This invention relates to a process for reducing poisonous effects ofmetal contaminants such as iron, nickel, vanadium and the like picked upby a hydrocarbon conversion catalyst during a hydrocarbon conversionprocess such as the high temperature conversion of a hydrocarbonfeedstock containing such metals to a lower boiling product. Moreparticularly, this invention relates to processes for reducing thepoisonous effects of metal contaminants without removal of suchcontaminants from the catalyst, e.g., by a process of passivation.

During a catalyst promoted chemical conversion metal contaminants suchas iron, nickel, copper and vanadium, the catalyst may become more andmore deactivated due to the pick up of at least a portion of such metalcontaminants. Removal of such poisons from the catalyst may restore asubstantial amount of the catalytic activity. However, no matter howcarefully the process for the removing the metal poisons from thecatalyst is carried out, some penalty in the form of overall performanceis often paid. Accordingly, a simple and straight forward method ofovercoming the deleterious effects of the metal poisons or contaminantsis desirable.

Catalytically promoted methods for the chemical conversion ofhydrocarbons include cracking, hydrocracking, reforming,hydrodenitrogenation, hydrodesulfurization, etc. Such reactionsgenerally are performed at elevated temperatures, for example, about300° to 1200° F., more often 600° to 1000° F. Feedstocks to theseprocesses comprise normally liquid or solid hydrocarbons which, at thetemperature of the conversion reaction, are generally in a fluid, i.e.,liquid or vapor, state and the products of the conversion usually aremore valuable, lower boiling materials.

Although referred to as "metals", these catalyst contaminants may bepresent in the hydrocarbon feed in the form of free metals or relativelynon-volatile metal compounds. It is, therefore, to be understood thatthe term "metal" as used herein refers to either form. Various petroleumstocks have been known to contain at least traces of many metals. Forexample, Middle Eastern crudes contain relatively high amounts ofseveral metal components, while Venezuelan crudes are noteworthy fortheir vanadium content and are relatively low in other contaminatingmetals such as nickel. In addition to metals naturally present inpetroleum stocks, including some iron, petroleum stocks also have atendency to pick up tramp iron from transportation, storage andprocessing equipment. Most of these metals, when present in a stock,deposit in a relatively non-volatile form on the catalyst duringconversion processes so that regeneration of the catalyst to removedeposited coke does not also remove these contaminants. With theincreased importance of gasoline in the world today and the shortages ofcrude oils and increased prices, it is becoming more and more importantto process any type or portions of a crude source, including thosehighly metal contaminated crudes to more valuable products.

Of the various metals which are to be found in representativehydrocarbon feedstocks some, like the alkali metals, only deactivate thecatalyst without changing the product distribution; therefore, theymight be considered true poisons. Others such as iron, nickel, vanadiumand copper markedly alter the selectivity and activity of crackingreactions if allowed to accumulate on the catalyst and, since theyaffect process performance, they are also referred to as "poisons". Apoisoned catalyst with these metals generally produces a higher yield ofcoke and hydrogen at the expense of desired products, such as gasolineand butanes. For instance, U.S. Pat. No. 3,147,228 reports that it hasbeen shown that the yield of butanes, butenes and gasoline, based onconverting 60 volume percent of cracking feed to lighter materials andcoke dropped from 58.5 to 49.6 volume percent when the amount of nickelon the catalyst increased from 55 ppm to 645 ppm and the amount ofvanadium increased from 145 ppm to 1480 ppm in a fluid catalyticcracking of a feedstock containing some metal contaminated stocks. Sincemany cracking units are limited by coke burning or gas handlingfacilities, increased coke or gas yields require a reduction inconversion or throughput to stay within the unit capacity.

Several U.S. patents exemplifying the passivation approach to reducingthe poisonous effects of metal contaminants on a conversion catalyst arediscussed hereinafter.

U.S. Pat. No. 2,901,419 (1959) discloses a method for preventingundesirable catalytic effects during a catalytic conversion of ahydrocarbon feedstock than would otherwise result from an accumulationof metal or metal-containing impurities, e.g., iron, nickel and/orvanadium, on a catalyst surface. The method comprises introducingtogether with the contaminated catalyst in a catalyst zone, at least onematerial selected from the group consisting of metals of the periodicsystem of Groups III and IV, and metals of the right-hand subgroups ofGroups I and II of the periodic system. Specific metals named from thecited groups were copper, silver, gold, tin, zinc, cadmium and mercury.The catalyst zone discussed in the examples was a muffle furnace at1000° F. for two hours. Powdered zinc and powdered zinc fluoride werethe only materials used in the examples to demonstrate the invention.

U.S. Pat. No. 3,711,422 (1973) discloses a method for restoring theactivity of metal contaminated cracking catalysts by a passivationprocess involving antimony containing compounds which are either oxidesor convertible to oxides of antimony upon calcination. The passivationprocess involves contacting the cracking catalyst withantimony-containing compounds so as to deposit them on the catalyst,e.g., by impregnation, dry mixing or deposition from suitable carryingagents.

U.S. Pat. No. 4,031,002 (1977) discloses a method for passivating metalcontaminants, e.g., nickel, vanadium and/or iron in a catalyst bycontacting such a catalyst with an antimony compound containingphosphorodithioate ligands having the following general formula:##STR1## wherein the R groups which can be the same or different arehydrocarbyl radicals containing from 1 to about 18 carbon atoms perradical, the total number of carbon atoms per antimony compound moleculebeing from 6 to about 90.

The disclosed phosphorus and antimony compounds can be added to thefeedstock prior to the cracking zone. There is no suggestion that thephosphorus present in the antimony compound plays an active role in themetals passivation process. Only the concentration of the antimonypresent in these compounds in relation to the amount of metalcontaminants either in the feed or on the contaminated catalyst areconsidered. The importance of the phosphorus beyond its usefulness inproviding a stable organic soluble antimony compound is neithersuggested nor disclosed.

U.S. Pat. Nos. 4,148,712 (1979) and 4,148,714 (1979) both disclose theuse of cracking catalyst fines from a cracking process wherein antimonyor a compound thereof had been used as a metals passivation agent formetals such as nickel, vanadium and/or iron. Phosphates, phosphites andthiophosphates of antimony compounds are cited. Oil-soluble antimonytris-(O,O-dihydrocarbyl dithiophosphates) are indicated to be preferred.

U.S. Pat. Nos. 4,153,536 (1979) a divisional of 4,111,845 discloses theuse of antimony and antimony-containing compounds to produce a crackingcatalyst containing antimony in an amount sufficient to inhibitdetrimental effects of metal contaminants such as nickel, vanadium andiron. Organic antimony compounds containing phosphorus atoms such asantimony phosphites, phosphates, thiophosphates and dithiophosphates arementioned. However, the importance, if any, of the phosphorus alone as apassivating agent itself is neither suggested nor disclosed. Thequantity of the antimony to be added to the cracking catalyst is theonly feature of the antimony-containing compounds considered. The amountof phosphorus transferred to the cracking catalyst, if any, is notdiscussed.

U.S. Pat. No. 4,167,471 (1979) discloses a particular method forintroducing a passivation stream, e.g., a fluid stream comprisinghydrocarbons and an antimony-containing metals passivating agent, at atemperature below the decomposition temperature of such agent, into acracking zone containing a cracking catalyst so as to maintain saidagent substantially free of thermal decomposition until contacting saidcracking catalyst. An example of such antimony-containing metalspassivating agent cited was disclosed previously in U.S. Pat. No.4,031,002 (1977) and contained phosphorodithioate ligands attached toantimony.

U.S. Pat. No. 4,169,784 (1979) discloses a method for the simultaneoususe of a metals passivation agent and an oxidation promoter in acatalytic cracking system. Antimony compounds are indicated to bepreferred for use as the metals passivation agent.

U.S. Pat. No. 4,169,042 (1979) discloses a treating agent for ahydrocarbon cracking catalyst. The adverse effects of nickel, vanadiumand iron on cracking catalysts is either precluded or reduced bycontacting the cracking catalyst with at least one treating agentselected from the group consisting of elemental tellurium, oxides oftelurium and compounds convertible to elemental tellurium or oxidesthereof during cracking or catalyst regeneration. The treating agent canbe used either prior to, during or after a cracking catalyst is used ina hydrocarbon conversion process. The manner in which the conventionalcracking catalyst is contacted with a modifying agent containingtellurium include solutions of water, hydrocarbon or aqueous acidscontacting the cracking catalyst to result in an impregnation followedby volatilization of the liquid or precipitation of tellurium-containingcompounds onto the catalyst from a treating solution.

Belgium Application 866,332, corresponding to (McKay) U.S. applicationSer. No. 819,027, (now U.S. Pat. No. 4,141,858) discloses the use ofantimony and/or bismuth-containing compounds to counteract thedeactivating effect of metal contaminants such as nickel, iron and/orvanadium on clay-based cracking catalysts. Bismuth phosphate wasexpressly cited as an example of a bismuth-containing compound.

U.S. Pat. No. 4,098,678 (Schwartzenbek 1978) discloses a method forovercoming that deactivation of a catalyst which is primarily due to theinfluence of steam used during hydrocarbon processing. The disclosedinvention broadly involves the addition of a silcon-containing compound,for example, silica acid, to steam employed in the cracking operations.Such steam used in the cracking operation is used for dispersing of anoil, stripping of a spent catalyst, airation of a stand pipe and thelike. The deactivation due to steam in the hydrocarbon processing isconcluded to be attributable to the silica solubilization in the steamwhich is substantially avoided by the addition of silica-containingcompounds to the steam. The additional silica-containing compounds tothe steam reduces the rate of silica solubilization from a catalyst intothe steam.

U.S. Pat. No. 4,183,803 (1980) discloses a process for the restorationof a used cracking catalyst, an improved catalytic cracking processwhich can provide a high yield and selectivity for gasoline and amodified cracking catalyst. The improved cracking catalyst involvesrestoring a used cracking catalyst contaminated by metals selected fromthe group consisting of nickel, vanadium and iron by contacting the usedcatalyst with antimony selenide, antimony sulfide, antimony sulfate,bismuth selenide, bismuth sulfide or bismuth phosphate.

The present invention is particulary suitable for passivating poisons ina catalyst utilized in the catalytic cracking of reduced or topped crudeoils to more valuable products, such as illustrated in U.S. Pat. Nos.3,092,568 and 3,164,542, the teachings of which are incorporated byreference herein. Similarly, this invention is applicable to processingshale oils, tar sands oils, coal oils and the like where metalcontamination of the processing, e.g., cracking, catalyst can occur.

BRIEF DESCRIPTION OF THE INVENTION

It is an object of this invention to improve the performance of ahydrocarbon conversion catalyst by reducing the poisonous effects ofmetals present in a hydrocarbon feedstock.

It is an object of this invention to use species of silicon-containingmaterial, alone or in combination with at least one aluminum and/orphosphorus-containing material to reduce the poisonous effects on achemical conversion catalyst of metal contaminants such as iron, nickel,vanadium and/or copper present in a hydrocarbon feedstock.

Other objects of this invention will be clear based upon thisdisclosure.

It has been discovered that treating a conversion catalyst containingmetal contaminants such as iron, copper, nickel and/or vanadium with atleast one silica-containing material and optionally, in combination withan aluminium and/or phosphorus-containing material significantly reducesthe poisonous effects of metal contaminants picked up by the catalystfrom a hydrocarbon feedstock during hydrocarbon processing. Optionally,but preferably, at least a portion of the hydrocarbon conversioncatalyst so treated is calcined before being returned to a hydrocarbonconversion zone. Several methods, to be discussed further hereinafter,for treating such a contaminated conversion catalyst have been found tobe surprisingly effective.

One unique aspect of this invention resides in the use ofsilica-containing material alone or in combination with aluminum and/orphosphorus-containing material to passivate metal contaminants in acatalyst by transfer to the catalyst of at least an effective amount ofsilicon atoms from the silicon-containing material alone or incombination with aluminum and/or phosphorus-containing atoms from thealuminum and/or phosphorus containing material.

It has also been discovered that treating in the substantial absence ofbismuth and/or antimony a conversion catalyst containing a metalcontaminant such as iron, copper, nickel and/or vanadium withphosphorus-containing compounds and preferably followed by calcination,the apparent poisonous effects of freshly deposited metal contaminantsupon a hydrocarbon conversion catalyst are significantly reduced. Theart discussed herein did not appreciate that phosphorus-containingmaterials or species in the substantial absense of any significantamount of antimony and/or bismuth-containing material can be veryeffective in reducing the deleterious effects of metal contaminants on aconversion catalyst and thereby to restore to a remarkable degree thecatalytic activity of such a treated conversion catalyst. "In thesubstantial absence of any significant amount of antimony and/orbismuth-containing material or species" is meant that the amount ofantimony and/or bismuth present, if any, would alone provide nomeasurable benefit toward restoring the activity of a poisoned catalystwhich is treated in accordance with patents cited herein, i.e., thepatents which involve the use of antimony and/or bismuth compounds topassivate metals such as nickel, vanadium and iron in a contaminatedcracking catalyst. Several methods, to be discussed hereinafter, fortreating such a contaminated catalyst have been found to be surprisinglyeffective.

We have found that the atomic ratio, i.e., the number of atoms of onespecie of atoms, e.g., the total atoms of silicon alone or of phosphorusand/or of aluminum, if any, to that of another specie or species ofatoms, e.g., the total number of atoms of metal contaminants to bepassivated, is preferably in the range of about 0.01 to about 3, andmore preferably in the range of about 0.03 to about 1. Further, it hasbeen discovered that the ratio of all silicon atoms to all phosphorusatoms to be transferred to a metal contaminated catalyst, e.g., acatalyst containing nickel, iron, vanadium and/or copper ascontaminants, is preferably in the range of about 0.1:1 to about 10:1,and still more preferably in the range of about 0.5:1 to about 5:1; andthat the ratio of all silicon atoms to all aluminum atoms to betransferred to a metal contaminated catalyst, e.g., a catalystcontaining nickel, iron, vanadium and/or copper as containants ispreferably in the range of about 0.1:1 to about 10:1 and still morepreferably in the range of about 0.5:1 to about 5:1.

Generally, any silicon, aluminum and/or phosphorus compound which is atleast partially soluble or sparingly soluble in a liquid medium used forcontacting a regenerated catalyst can be used or which is soluble in thehydrocarbon feed can be used. For a material to be "sparingly soluble"in a liquid medium or solvent means at least 0.01 grams of that materialcan be dissolved in 100 milliliters of solvent.

Solid oxide catalysts have long been recognized as useful incatalytically promoting the conversion of hydrocarbons. For hydrocarboncracking processes carried out in the substantial absence of added freemolecular hydrogen, suitable catalysts which are usually activated orcalcined, are predominately silica or silica-based, e.g.,silica-alumina, silica-magnesia, silica-zirconia, etc., compositions ina state of slight hydration containing small amounts of acidic oxidepromoters in many instances. The oxide catalyst may contain asubstantial amount of a gel or gelatinous precipitate comprising a majorportion of silica and at least one other inorganic oxide material, suchas alumina, zirconia, etc. These oxides may also contain small amountsof other inorganic materials. The use of wholly or partially syntheticgel or gelatinous catalyst, which are uniform and little damaged by hightemperatures in treatment and regenerating, is often preferable.

Also suitable are hydrocarbon cracking catalysts which include acatalytically effective amount of at least one natural or syntheticzeolite, e.g., crystalline alumino silicate. A preferred catalyst is onethat includes at least one zeolite to provide a high activity catalyst.Suitable amounts of zeolite in the catalyst are in the range of about1-75% by weight. Preferred are zeolite amounts of about 2-30% by weightof the total catalyst. Catalysts which can withstand the conditions ofboth hydrocarbon cracking and catalyst regenerating are suitable for usein the process of this invention. For example, a phosphatesilica-alumina silicate composition is shown in U.S. Pat. No. 3,867,279,chrysotile catalysts are shown in U.S. Pat. No. 3,868,316, zeolite betatype of catalyst is shown in U.S. Pat. No. Re. 28,341. The catalyst maybe only partially of synthetic material; for example, it may be made bythe precipitation of silica-alumina on clay, such as kaolinite orhalloysite. One such semi-synthetic catalyst contains about equalamounts of silica-alumina gel and clay.

The manufacture of synthetic gel catalyst is conventional, well known inthe art and can be performed, for instance (1) by impregnating silicawith aluminia salts; (2) by direct combination of precipitated (orgelated) hydrated alumina and silica in appropriate proportions; or (3)by joint precipitation of alumina and silica from an aqueous solution ofaluminum and silicon salts. Synthetic catalyst may be produced by acombination of hydrated silica with other hydrate bases as, forinstance, zirconia, etc. These synthetic gel-type catalysts may beactivated or calcined before use.

A particularly preferred catalyst contains a catalytically effectiveamount of a decationized zeolitic molecular sieve having less than 90%of the aluminum atoms associated with cations, a crystalline structurecapable of internally absorbing benzene and a SiO₂ to Al₂ O₃ molar ratiogreater than 3. Such catalysts are illustrated in U.S. Pat. No.3,236,761, the teachings of which are incorporated by reference herein.

The physical form of the catalyst is not critical to the presentinvention and may, for example, vary with the type of manipulativeprocess in which it will be used. The catalyst may be used as a fixedbed or in a circulating system. In a fixed-bed process, a singlereaction zone or a series of catalytic reaction zones may be used. If aseries of reactors are used, one is usually on stream and others are inthe process of cleaning or regenerating and the like. In circulatingcatalyst systems, such as those of the fluid bed or moving bed catalyticprocesses, catalyst moves through a reaction zone and then through aregeneration zone. In a fluid bed cracking process, gases are used toconvey the catalyst and to keep it in the form of a dense turbulent bedwhich has no definite upper interface between the dense (solid) phasethe suspended (gaseous) phase mixture of catalyst and gas. This type ofprocessing requires the catalyst to be in the form of a fine powder,e.g., a major amount by weight of which being in a size range of about20 to 150 microns. In other processes, e.g., moving bed catalyticcracking system, the catalyst can be in the form of macrosize particlessuch as spherical beads which are conveyed between the reaction zone andthe catalyst regeneration zone. These beads may range in size up toabout 1/2" in diameter. When fresh, the minimum size bead is preferablyabout 1/8". Other physical forms of catalyst such as tablets, extrudedpellets, etc. can be used.

In this invention, the hydrocarbon petroleum oils utilized as feedstockfor a given conversion process may be of any desired type normallyutilized in such hydrocarbon conversion operations. The feedstock maycontain nickel, iron and/or vanadium as well as other metals. Asindicated, the catalyst may be used to promote the desired hydrocarbonconversion by employing at least one fixed bed, moving bed or fluidizedbed (dense or dilute phase) of such catalyst. Bottoms from hydrocarbonprocesses, (i.e., reduced crude and residuum stocks) are particularlyhighly contaminated with these metals and, therefore, rapidly poisoncatalysts used in converting bottoms to more valuable products. Forexample, a bottom may contain about 100-1500 ppm Ni, about 100-2500 ppmV and about 100-3000 ppm Fe. For typical operations, the catalyticcracking of the hydrocarbon feed would often result in a conversion ofabout 10 to 80% by volume of the feedstock into lower boiling, morevaluable products.

Broadly, this invention is an improvement to a conventional conversionprocess. A conventional conversion process involves contacting ahydrocarbon feedstock in a reaction zone at hydrocarbon conversionconditions with a catalyst to form a conversion product and adeactivated catalyst which has carbonaceous deposits and contains atleast a portion of the metal contaminants such as nickel, iron, vanadiumand/or copper originally present in the hydrocarbon feedstock. Thedeactivated catalyst is typically regenerated to restore at least aportion of its catalytic activity by removing under controlledconditions at least a portion of said carbonaceous deposits to form aregenerated catalyst.

An example of a conversion process is cracking of hydrocarbon feedstocksto produce hydrocarbons of preferred octane rating boiling in thegasoline range. A variety of solid oxide catalysts is widely used togive end products of fairly uniform composition. Cracking is ordinarilyeffected to produce gasoline as the most valuable product and isgenerally conducted at temperatures of about 750° to 1100° F.,preferably about 850° to 950° F., at pressures up to about 2000 psig,preferably about atmospheric to 100 psig and without substantialaddition of free hydrogen to the system. In cracking, the feedstock isusually a petroleum hydrocarbon fraction such as straight run or recyclegas oils or other normally liquid hydrocarbons boiling above thegasoline range. Recently, low severity cracking conditions have beenemployed for heavily contaminated feedstocks such as crude or reducedcrude where the conversion is not made directly to the most valuable,lower boiling products, i.e., gasoline boiling range products, but tointermediate type hydrocarbon conversion products which may be laterrefined to the more desirable, lower boiling, gasoline or fuel oilfractions. High severity cracking has also been practiced for theconversion of such feedstocks to light, normally gaseous hydrocarbons,such as ethane, propane or butane.

An example of a regeneration procedure is one wherein the catalyst iscontacted periodically with free oxygen-containing gas in order torestore or maintain the activity of the catalyst by removing at least aportion of the carbonaceous deposits from the catalyst which form duringhydrocarbon conversion. However, in those processes not having aregeneration step, the catalyst can be subjected to a regenerating stepafter the removal of the catalyst from the process. It will beunderstood that "regeneration" involves a carbonaceous material burn-offprocedure. Ordinarily, the catalyst is taken from the hydrocarbonconversion system and treated before the poisoning metals have reachedan undesirably high level, for instance, above about 0.5% by weight, oncatalyst and prferably less than about 10% maximum, content of nickel,iron and vanadium. More preferably, the catalyst is removed when thenickel, iron and vanadium content is less than about 5% by weight andmost preferably when the catalyst contains about 0.75% to about 2% byweight nickel, iron and vanadium. Generally speaking, when thehydrocarbon conversion levels, i.e., more than about 50% by volume (ofthe feedstock) conversion, the amount of metals tolerated on thecatalyst is less. On the other hand, low conversion levels, i.e., lessthan about 50% by volume conversion, tolerate higher amounts of metalson the catalyst.

The actual time or extent of the regeneration thus depends on variousfactors and is dependent on, for example, the extent of metals contentin the feed, the level of conversion, unit tolerance for poison, thesensitivity of the particular catalyst toward the passivation procedureused to reduce the poisonous effects of metals upon the catalyst, etc.

Regeneration of a hydrocarbon cracking catalyst to remove carbonaceousdeposit material is conventional and well known in the art. For example,in a typical fluidized bed cracking unit, a portion of catalyst iscontinually being removed from the reactor and sent to the regeneratorfor contact with an oxygen-containing gas at about 950° to about 1220°F., preferably about 1000° to about 1150° F. Combustion of carbonaceousdeposits from the catalyst is rapid, and, for reasons of economy, air isused to supply the needed oxygen. Average residence time for a catalystparticle in the regenerator can be on the order of about three to onehundred minutes, preferably about three minutes to sixty minutes and theoxygen content of the effluent gases from the regenerator is desirablyless than about 0.5 weight percent. When later oxygen treatment isemployed, the regeneration of any particular quantity of catalyst isgenerally regulated to give a carbon content remaining on the catalystof less than about 0.5 weight percent. At least a portion of theregenerated catalyst is then returned to the reaction zone.

Calcination of a hydrocarbon cracking catalyst involves heating at hightemperatures, e.g., 950° to 1200° F., in a molecular oxygen-containinggas. The temperature preferably is at least about 50° F. higher than theregeneration temperature, but below a temperature where the catalystundergoes any substantial deleterious change in its physical or chemicalcharacteristics. The catalyst is in a substantially carbon-freecondition during a calcination treatment, because the burning off of anysignificant amount of carbon on the catalyst would lead to, at least inthe area where such carbon was located, the evolution of such amounts ofheat energy that the catalyst near such evolution of heat energy wouldvery likely be damaged.

The improved process of this invention comprises: contacting aregenerated catalyst with a liquid medium containing an effectiveamount, to be discussed in more detail hereinafter, of one or moresilicon-containing materials alone or in combination with aluminumand/or phosphorus-containing materials, all of which are at least inpart soluble within said liquid medium, to form a treated catalyst andoptionally, but preferably, separating the treated catalyst from atleast a portion of said liquid medium and transferring at least aportion of the treated catalyst to said reaction zone.

The transfer of treated catalyst to the reaction zone is intended toinclude both direct and/or indirect transfer to the reaction zone. Forexample, the treated catalyst can be returned to the regenerator, or azone for calcination, or to the hydrocarbon feedstock before, after orsubstantially simultaneously as that feedstock is being introduced intothe reaction zone.

The time of contacting is sufficient to permit a sufficient amount ofthe silicon-containing material alone or in combination with aluminumand/or phosphorus-containing material to react with the regeneratedcatalyst to form a treated catalyst. The order of contacting theregenerated catalyst with silicon, phosphorus and/or aluminum-containingmaterial or species has been found to be generally unimportant. Thecontacting with silicon and phosphorous-containing species may bealternately in the same or different liquid mediums, first silicon thenphosphorus-containing species, or vice versa, or substantiallysimultaneously from a single liquid medium containing both species. Thesame is true for silicon and alumina.

The effective amount of silicon, aluminum and/or phosphorus-containingmaterials or species present in the liquid medium cannot be preciselydefined, but it is preferably an amount which results in the treatedcatalyst having an atomic ratio of silicon, aluminum and/or phosphorusatoms from all silicon, aluminum and/or phosphorus-containing species,to total number of atoms of metal contaminants, e.g., of unpassivatednickel, vanadium, iron and/or copper in the treated catalyst in therange of about 0.01 to about 3, and preferably in the range of about0.03 to about 1. Atomic ratio of a first material or specie of atoms toa second material or specie of atoms means, throughout thisspecification and claims, the ratio of the total number of atoms of thefirst material or specie, regardless of any oxidation state or statestherein, to the total number of atoms of the second specie, regardlessof any oxidation state or states therein.

For example, when the concentration of contaminating metals, calculatedas a respective element thereof, in the catalyst is within the range ofabout 0.2% to about 3.5% by weight, as based upon the total weight ofthe catalyst, a particularly useful liquid, e.g., water, mediumconcentration in moles/liter of silicon, aluminum and/orphosphorus-containing species, calculated as based on the respectiveelement of the specie present, is in the range of about 0.03 mole/literto about 1.0 mole/liter. The percent by weight of catalyst in such aliquid medium is not critical, but is preferably in the range of about10 to 40 percent by weight.

The liquid medium referred to above can be either an aqueous medium oran organic medium. Both the aqueous medium and the organic medium shouldbe substantially free from contaminating metals such as discussedearlier. The terms "substantially free", means throughout thisspecification and claims, present in a concentration sufficiently low soas not to contaminate a catalyst treated by such a medium to a degreethat measurably and adversely degrades the selectivity and/or activityof the catalyst so treated. Example of such aqueous media are distilledwater and deionized water. Examples of suitable organic media arepetroleum distillates, liquid hydrocarbons, such as benzene, toluene,naphthenes and the like.

Examples of suitable silicon compounds which are particularly effectivein an aqueous medium treatment of a conversion catalyst are: colloidalSiO₂ ; silanes having the general formula Si_(n) H_(2n+2) where n is aninteger in the range of from 1 to 10; siloxanes having the generalformula H₃ Si(OSiH₂)_(n) OSiH₃ where n is an integer in the range offrom 0 to 10; Si(Ac)₄ ; H₄ SiO₃ ; M₂ SiO₃, and M₄ SiO₄ where M is amonovalent metal ion selected from the group consisting of group 1a ofthe Periodic Table of elements. Ac means an acetate anion throughoutthis specification. Colloidal SiO₂ is commercially available andconsists of particles of SiO₂ having dimensions in the range of about0.001 micron to about 1 micron. Ultrafine grinding can be used toprepare a colloidal dispersion of SiO₂.

Examples of suitable silicon compounds which are particularly effectivein an organic medium treatment of a conversion catalyst are: silaneshaving the general formula Si_(n) H_(2n+2) wherein n is an integer inthe range from 1 to 10; siloxanes having the general formula H₃Si(OSiH₂)_(n) OSiH₃ wherein n is an integer in the range of from 1 to10; Si(A)₄ wherein A is selected from the group of carboxylic acidscontaining up to four carbon atoms; a compound having a formula selectedfrom the group consisting of: Si(OR)₄ and (RO)₃ SiOSi(R)₃ wherein each Ris individually selected from the group consisting of compoundscontaining only carbon and hydrogen atoms, i.e., a hydrocarbyl materialwherein the number of carbon atoms is in the range of from 1 to 20, ahalogen substituted hydrocarbyl material, i.e., a material, wherein atleast one hydrogen of a hydrocarbyl material has been replaced by ahalogen selected from the group consisting of fluorine, chlorine,bromine and iodine; a cyclosilane compound having a general formula(SiH.sub. 2)_(n) wherein n is an integer in the range 2 to 5; acyclosiloxane compound having a general formula (SiH₂.O)_(n) wherein nis an integer in the range of from 3 to 10; a silazane having a generalformula H₃ Si(NHSiH₂)nNHSiH₃ wherein n is an integer in the range offrom 0 to 10; a cyclosilazane having a general formula (SiH₂.NH)_(n)wherein n is an integer in the range of from 2 to 15; a compound havinga general formula selected from the group consisting: R_(n) SiH_(4-n),and R_(n) Si(OH)_(4-n) wherein n is an integer in the range of 1 to 4and wherein each R is individually selected from the group consisting ofa hydrocarbyl material having up to 20 carbon atoms and a halogensubstituted hydrocarbyl material having up to 20 carbon atoms whereinsaid halogen is selected from the group consisting of fluorine,chlorine, bromine and iodine; a compound having a general formulaselected from the group consisting of: (RO)_(n) SiH_(4-n) and (RO)_(n)Si(OH)_(4-n) wherein each R is individually selected from the groupconsisting of a hydrocarbyl material having up to 20 carbon atoms and ahalogen substituted hydrocarbyl material having up to 20 carbon atomswherein said halogen is selected from the group consisting of fluorine,chlorine, bromine and iodine and wherein n is an integer in the range offrom 1 to 4; a compound having a general formula SiSX₂ wherin each X isindividually selected from the group consisting of bromine and chlorineand S is sulfur; a hexahalodisiloxane having the general formula Si₂ OX₆wherein each X is individually selected from the group of halogensconsisting of fluorine, chlorine, bromine and iodine; and a compoundhaving a formula selected from the group consisting of: ((RO)₃ Si)₂ O,(R₃ Si)₂ O and (R₃ Si)₂ S wherein S is sulfur and each R of saidcompound is selected from the group consisting of hydrogen, ahydrocarbyl material having up to 5 carbon atoms and a halogensubstituted hydrocarbyl material having up to 5 carbon atoms; a compoundhaving the general formula ((RO)₃ Si)₂ O wherein each R is individuallyselected from the group consisting of a hydrocarbyl material having upto 5 carbon atoms and of a halogen substituted hydrocarbyl materialshaving up to 5 carbon atoms; and a compound having a formula selectedfron the group consisting of (RO)_(n) Si(OH)_(4-n) and (R)_(n)Si(OH)_(4-n) wherein each R is individually selected from the groupconsisting of a hydrocarbyl material having up to 5 carbon atoms and ofa halogen substituted hydrocarbyl material having up to 5 carbon atomsand wherein n is an integer in the range of 1 to 3.

Examples of suitable aluminum compounds which have been foundparticularly effective in an aqueous solution treatment of conversioncatalyst are: Al(NO₃)₃, Al₂ (SO₄)₃, AlPO₄, Al(C₆ H₅ O)₃, Al(Ac)₃,wherein Ac is acetate, (NH₄ Al(SO₄)₂, (Al(BrO₃)₃, Al(ClO₄)₃, Al(C₂ H₅O)₃, Al-lactate, Al-oleate and AlX₃ wherein each X is individuallyselected from the group of halogens consisting of F, Cl, Br and I.

Generally, any aluminum compound which is at least partially soluble orsparingly soluble in an organic medium can be used to contact aregenerated catalyst or which is soluble or sparingly soluble in thehydrocarbon feed can be used. For a material to be sparingly soluble ina solvent means at least 0.01 grams of that material can be dissolved in100 milliliters of solvent. Some examples of organic compounds that canbe used are: diketonates; sulfonates; dithiophosphates; alkoxides;carboxylates having from 1 to 20 carbon atoms; such as stearates andoleates; phenoxides; naphthenates; aluminum hydrocarbyls; such as alkylshaving the formula R₃ Al wherein each R individually contains from 1 to20 carbon atoms; hydrocarbyl aluminum halides having the formula R_(n)AlX_(3-n) wherein n can have values of 1 or 2 and each R is individuallyselected from a group consisting of hydrocarbyl and halogen substitutedhydrocarbyl material having up to 20 carbon atoms wherein the halogen isindividually selected from fluorine, chlorine, bromine and iodine;alkylalkoxyaluminum having the formula R_(n) Al(R'O)_(3-n) wherein eachR and R' individually is selected from a group consisting of hydrocarbyland halogen substituted hydrocarbyl materials having from 1 to 20 carbonatoms and wherein n is an integer in the range of from 0 to 3;carbonyls, metallocenes, hydrocarbyl, such as alkyl and aryl phosphineand phosphite complexes wherein the hydrocarbyl has 1 to 20 carbonatoms; aluminum oxalates; aluminum acetates; aluminum diethylmalonate;aluminum 1-phenolsulfonates and aluminum halides wherein the halide isselected from a group of halides consisting of fluorine, chlorine,bromine, iodine and mixtures thereof.

Examples of suitable phosphorus compounds which are particularlyeffective in an aqueous solution treatment of a conversion catalyst are:P₂ O₅, H₃ PO₄, (NH₄)₃ PO₄, (NH₄)₂ HPO₄, (NH₄)H₂ PO₄, H₄ P₂ O₇, PSBr₃, H₃PO₂, H₃ PO₃, (NH₄)₂ H₂ P₂ O₇ and phosphorylamide (PO(NH₂)₃).

Examples of suitable phosphorus compounds which are particularlyeffective in an organic medium are: R₃ P, (RO)₃ P, (RO)₃ PO and R₃ POwhere each R of the preceding four formulas is individually selectedfrom the group consisting of compounds containing only carbon andhydrogen such as alkyl, aralkyl, alkenyl, aralkenyl, i.e., a hydrocarbylmaterial, having from 1 to 35 carbon atoms and a halogen substitutedhydrocarbyl material having from 1 to 35 carbon atoms wherein at leastone hydrogen of said hydrocarbyl materia is replaced with a halogenselected from a group consisting of fluorine, chlorine, bromine andiodine; POX₃, PSX₃, PX₅ and PX₃ where each X of the preceding fourformulas is individually selected from the group consisting of fluorine,chlorine, bromine and iodine; P₄ S₇, P₂ S₅, P₄ S₄, P₄ O₆ S₄ P(SCN)₃,(PNCl)_(x) where x can be 2 or 3, P₄, P₂ O₃, H₃ PO₃ and H₃ PO₂. In thepreceding formulas and wherever used throughout this specification: P isphosphorus; O is oxygen; S is sulfur; N is nitrogen; and Cl is chlorine.

In still another method for passivating the poisonous effects of metalcontaminants on a conversion catalyst is to introduce into thehydrocarbon feed of a conventional conversion process at least onepartially soluble silicon-containing material or compound alone or incombination with phosphorus and/or aluminum-containing material before,after or simultaneously with contacting the catalyst in a reaction zonewith that hydrocarbon feed In this method there is no need to separatelycalcine the catalyst as the substantially simultaneous deposition ofboth the silicon-containing material alone or in combination withphosphorus-containing and/or aluminum-containing material and othermetal contaminants within the hydrocarbon feedstock have been found tosurprisingly work together to maintain the activity of the conversioncatalyst. The atomic ratio of all silicon, phosphorus and/or aluminumatoms to all metal contaminants in the hydrocarbon feed has an impactupon the observed results. For example, if the ratio is much in excessof 3, then the catalytic activity of the catalyst may be adverselyeffected. If, on the other hand, the ratio is much less than about 0.01,then the observed benefits are correspondingly lessened. Generally, somebenefits of this invention are obtained when the atomic ratio of allsilicon, phosphorus and/or aluminum to all metal contaminants in thehydrocarbon feed is in the range of about 0.01 to about 3, andpreferably when the ratio is in the range of about 0.03 to about 1.

Examples of processing conditions useful in carrying out a process ofthis invention are set out hereinafter. Contacting times between acatalyst and a liquid medium for aqueous media are generally in therange of from about half a second to about twenty minutes and preferablyin the range of from about two minutes to about ten minutes. Contactingtimes for an organic medium is about the same as for an aqueous medium,but often depends upon the rate at which the organic medium can beevaporated off, and hence does not have a simply definable contactingtime. The temperature of the contacting medium, e.g., organic andaqueous media, can be any where from about ambient or room temperature(72° F.) to the boiling point of the contacting medium. Temperature isnot critical and may, in fact, be below room temperature, but we havefound no reason for cooling in order to obtain the benefits from aprocess of this invention.

It has further been found that contact with oxidative washes, i.e., anaqueous solution containing an oxidizing agent or an agent capable ofaccepting electrons, has a beneficial effect of further improving thecatalytic activity of a silicon, phosphorus and/or aluminum treated orpassivated conversion catalyst which contains metal contaminants. The"wash" refers to a treatment which may be carried out in a variety ofways, e.g., batch operation, semi-continuous or continuous operationwith or without counter currents. The passivated catalyst is contactedwith the oxidative or wash solution for a time sufficient to cause aninteraction between the solution and catalyst that results in ameasurable benefit. The amount of metal contaminants removed from theconversion catalyst by these oxidative washes is generally very smalland apparently works by a mechanism different from that of ademetallization process such as disclosed in U.S. Pat. Nos. 4,102,811(1978); 4,163,709 (1979), and 4,163,710 (1979), which patents areexpressly incorporated herein by reference.

A preferred oxidative wash medium comprises a solution of hydrogenperoxide in water. Other oxidizing agents which may be used include air,oxygen, ozone, perchlorates, organic hydroperoxides, organic peroxides,organic peracids, inorganic peroxyacids such as peroxymonosulfuric andperoxydisulfuric acid, singlet oxygen, NO₂, N₂ O₄, N₂ O₃, superoxidesand the like. Typical examples of organic oxidants are hydroxyheptylperoxide, cyclohexanone peroxide, tertiary butyl peracetate, di-tertiarybutyl diperphthalate, tertiary butyl perbenzoate, methyl ethylhydroperoxide, di-tertiary butyl peroxide, p-methyl benzenehydroperoxide, naphthylhydroperoxide, tertiary butyl hydroperoxide,pinane hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, cumenehydroperoxide and the like; as well as organic peracids such asperformic acid, peracetic acid, trichloroperacetic acid, perchloricacid, periodic acid, perbenzoic acid, perphthalic acid and the likeincluding salts thereof. Ambient oxidative wash temperatures can beused, but temperatures of about 150° F. to the boiling point of theaqueous solution in combination with agitation are helpful. Preferredtemperatures are about 150° F. to about 203° F.

The hydrogen peroxide solution preferably containing about 2 to 30weight % hydrogen peroxide, can be added to an queous catalyst slurry asdescribed earlier at about 150°-203° F., more preferably 140°-185° F.and allowed to react for a time sufficient to produce a useful result.Preferred wash times are about 1-5 minutes. A concentration of H₂ O₂ inthe range of about 5-50 lb., preferably about 10-20 lb. of H₂ O₂ /ton ofcatalyst is preferably used. Additional oxidative washes can be used toensure the restoration of catalytic properties. In addition, theoxidative washing can be carried out either in the presence of orabsence of a mineral acid such as HCl, HNO₃ or H₂ SO₄. Preferably the pHof the oxidative wash medium is about 3 to about 6.

After the catalyst is washed, the catalyst slurry can be filtered togive a cake. The cake may optionally be reslurried one or more timeswith water or rinsed in other ways, such as, for example, by a waterwash of the filter cake.

After the washing and rinsing treatment, the catalyst is transferred toa hydrocarbon conversion system, for instance, to a catalystregenerator. The catalyst may be returned as a slurry in the finalaqueous wash medium, or it may be desirable first to dry the catalystfilter cake or filter cake slurry at, for example, about 215° to 320°F., under a vacuum, e.g., of less than one atmosphere. Also, prior toreusing the catalyst in the conversion operation it can be calcined, forexample, at temperatures usually in the range of about 700° F. to about1300° F. The catalyst may also be slurried with hydrocarbons and addedback to the reactor vessel, if desired.

The following examples are intended to be illustrative of the inventionof this disclosure. However, many variations based on the teachings ofthis disclosure are readily apparent to one skilled in the art and areintended to be within the scope of this invention. The examples shouldnot be used to unnecessarily restrict the nature and scope of thisinvention.

EXAMPLE I

A Phillips Borger equilibrium silica-alumina zeolite-containing catalystis used. This catalyst includes about 5% by weight of a crystallinealuminum silicate effective to promote hydrocarbon cracking having aninitial catalytic activity as follows:

    ______________________________________                                                     Catalytic Activity                                                            MA      CPR       H.sub.2 /CH.sub.4                              ______________________________________                                        Original Catalyst                                                                            80        0.75      8.0                                        ______________________________________                                    

The catalyst was used in a fluid catalytic cracking conversion of ahydrocarbon feedstock containing iron, nickel, copper, and vanadium. Thecontaminated catalyst was removed from the hydrocarbon conversion streamand regenerated to remove carbon under conventional regenerationconditions, so as to have less than about 0.5% by weight of carbon. Theregenerated catalyst had a catalytic activity, surface area (meterssquared per gram), and a metal contamination shown in the following:

    ______________________________________                                        % Metal    Catalytic      *Surface                                            Contaminants                                                                             Activity       Area                                                Ni   Fe     V      MA   CPF  H.sub.2 /CH.sub.4                                                                    Total   Zeolite                           ______________________________________                                        0.33 0.72   0.71   59.1 3.02 20.0   99      22                                ______________________________________                                         *Areas in meters squared per gram were determined in the case of total        area following ASTM D 3663 (1978) which involved an adsorptiondesorption      as in the BET method and in the case of the area attributable to zeolite      following a procedure disclosed by M. F. L. Johnson in The Journal of         Catalysis, 1978, V. 52, pg. 425.                                         

The regenerated catalyst was treated with a mixed solution of silicontetraethoxide, (C₂ H₅ O)₄ Si, and aluminum isopropoxide, Al(iPrO)₃, inchloroform under reflux conditions for twenty minutes. The atomic ratiosof Si and Al to total metal contaminants on the catalyst in the mixedsolution were 2.0:1 (Si:metal) and 1-0:1.0 (Al:metal). The solvent wasevaporated off to harvest solid treated catalyst, dried at 220° F. undervacuum and an oxidative wash with H₂ O₂ was repeated twice. Calcinationof the product at 1000° F. for 4 hours was followed to obtain the finaltreated catalyst. Detailed results are summarized in TABLE 1. The finalcatalyst treated in this manner exhibited unusually high catalyticactivities, which are also reflected by an increase in total surfacearea from 99 m² /g (for untreated catalyst) to 110 m² /g.

                  TABLE 1                                                         ______________________________________                                         Passivation of Metal Poisoned FCC Catalyst                                   Feed Catalyst: Phillips Borger Equilibrium Catalyst                           Passivating Agent: (EtO).sub.4 Si + Al(iPrO).sub.3                                                              To-                                                                           tal                                                                           Sur-                                        % Metal            Catalyst Activity                                                                            face                                        Ni        Fe     V      Ce   MA   CPF  H.sub.2 /CH.sub.4                                                                    Area                            ______________________________________                                        Contam-                                                                              0.33   0.72   0.71 0.10 59.1 3.01 20.2    99                           inated                                                                        Catalyst                                                                      Treated                                                                              0.30   0.67   0.54 0.10 74.1 1.33 3.92   110                           Catalyst                                                                      ______________________________________                                    

EXAMPLE II

A regenerated metal contaminated catalyst as disclosed in EXAMPLE I wasallowed to react with an aqueous silica colloidal solution at roomtemperature under agitation for about 30 minutes. The catalyst (20 g.)was slurried in 80 ml containing 9.6 grams colloidal silica solution(7.5 weight % SiO₂) and the passivation procedure was carried out asdescribed above. During this period the turbid SiO₂ colloidal solutionbecame clear due to deposition of SiO₂ on the catalyst surface. Thecatalyst was filtered, a clear filtrate discarded, and the catalyst soseparated was dried under vacuum at 220° F. for 6 hours. The driedcatalyst was then washed with a dilute solution of H₂ O₂ (20#H₂ O₂ /toncatalyst) at 160° F. for 4 minutes. The same wash procedure was repeatedin the 20% catalyst slurry system. Catalytic activities of the finalcatalyst are summarized in entry 1 of TABLE 2. In the oxidative washstep with H₂ O₂ , some vanadium, 25% including 8% removal in the silicatreating stage, was achieved, but both nickel and iron concentrationswere substantially unchanged. However, remarkable improvements in thecatalytic performance were noted in the silica treating step (entry1.a., TABLE 2), and further improvement was accomplished in thefollowing H₂ O₂ wash (entry 1.b., TABLE 2).

EXAMPLE III

Twenty grams of the same Phillip's Borger catalyst of EXAMPLE II wasallowed to react under reflux conditions in a silica tetraethoxidesolution wherein 1.20 grams of silica tetraethoxide, Si(C₂ H₅ O)₄, wasdissolved in 80 ml of chloroform. After reaction was carried out for 15minutes with vigorous agitation at ambient temperature (72° F.),chloroform was evaporated off the system to obtain a solid catalyst. Thecatalyst obtained in this way was dried in a vacuum oven at 210° F. for10 hours, and followed by calcination of the dried catalyst at 1100° F.for 4 hours. An oxidative wash of H₂ O₂ was achieved by the sameprocedure used in EXAMPLE II. Results are listed in entry 2, TABLE 2. Anunexpectedly high level of the catalytic activity of the final treatedcatalyst was reflected by the increase in the surface areas. The atomicratio of Si to total metal on the equilibrium catalyst was 2:1 in thisexperiment.

                                      TABLE 2                                     __________________________________________________________________________     Passivation of Metal Poisoned FCC Catalyst                                   Feed Catalyst: Phillip's Borger Equilibrium Catalyst                          Passivating Agent: Silica Deposition                                                          % Metal     Cat. Activity                                                     Ni Fe V  Ce MA CPF                                                                              H.sub.2 /CH.sub.4                                                                  Total                                                                             Zeolitic M.sup.2 /g                __________________________________________________________________________      Contaminated Catalyst                                                                       0.33                                                                             0.72                                                                             0.71                                                                             0.10                                                                             59.1                                                                             3.01                                                                             20.2  99 22                                   a. Colloidal SiO.sub.2 (7.5 wt %)                                             deposit, dried.                                                                             0.32                                                                             0.73                                                                             0.65                                                                             0.10                                                                             65.6                                                                             2.33                                                                             10.70                                                                              --  --                                   b. H.sub.2 O.sub.2 wash                                                                     0.33                                                                             0.72                                                                             0.53                                                                             0.10                                                                             72.1                                                                             1.54                                                                             7.11 --  --                                   (EtO).sub.4 Si (2 Si/metal)                                                   reflux in CHCl.sub.3, dried,                                                  and calcined at 1100° F.,                                              4 hr. H.sub.2 O.sub.2 wash followed.                                                        0.31                                                                             0.67                                                                             0.54                                                                             0.11                                                                             70.5                                                                             1.17                                                                             5.72 105 31                                 __________________________________________________________________________

EXAMPLE IV

Twenty grams of the regenerated Phillip's Borger catalyst of EXAMPLE 1,after first being water washed, was slurried at room temperature (72°F.) in a triphenylphosphite solution in chloroform. Wherein 2.90 gramsof triphenylphosphite, (C₆ H₅ O)₃ P was dissolved in 10 ml ofchloroform. The resulting slurry system was allowed to react for 20minutes. The atomic ratio of P to total metal was adjusted to be 1.5:1.The solvent was then evaporated off to obtain a treated solid catalyst.It was dried at 240° F. in a vacuum oven for 14 hours, and calcined at1100° F. for 4 hours. The resultant catalyst was further treated withcolloidal silica (5 weight % based on the catalyst) in an aqueoussolution. The slurried mixed system was stirred at room temperature for30 minutes. The catalyst was then filtered and washed with H₂ O₂ (20#H₂O₂ /ton catalyst). A 20 weight % catalyst slurry in water was allowed toreact with H₂ O₂ at 160° F. for about 4 minutes. After the liquidportion was decanted off, the same wash procedure was repeated again.The finished catalyst was filtered, dried and calcined at 1100° F. for 4hours. Metal removals and catalytic activities of the two stepsdescribed above are summarized in entries 1.a. and 1.b. in TABLE 3.

EXAMPLE V

The regenerated Phillip's Borger equilibrium catalyst of EXAMPLE 1 (20grams) was allowed to react in a triphenylphosphite solution inchloroform, 3.86 g. (C₆ H₅ O)₃ P in 80 ml chloroform, under refluxconditions for 15 minutes. The chloroform solvent was evaporated off andthe resulting catalyst was further treated in an organic solution ofsilicon tetraethoxide, 2.40 grams of Si(C₂ H₅ O)₄ dissolved in 60 mlchloroform, under reflux for 15 minutes. The solvent was evaporated offagain, dried and calcined at 1100° F. for 4 hours. The atomic ratio ofP:Si:total metal was adjusted to be 2:2:1 in this example. Results ofthe final treated catalyst are listed in entry 2, TABLE 3.

EXAMPLE VI

The water washed Phillip's Borger equilibrium catalyst described inEXAMPLE I, was allowed to react with triphenylphosphite under refluxconditions for 15 minutes. 40 grams of the water-washed and driedcatalyst was added to 120 ml of a triphenylphosphite solution in CHCl₃,1.93 grams of (C₆ H₅ O)₃ P in 120 ml of CHCl₃. The atomic ratio of P tototal metal contaminants was adjusted to be 0.5:1 in the reaction. Thesolid catalyst was obtained by evaporating off the solvent, and thetreated catalyst was divided into two equal parts. The first part wasdried, calcined at 1100° F. for 4 hours. The calcined catalyst waswashed with an aqueous hydrogen peroxide as described in previousexamples. The remaining half of the catalyst from the phosphite treatingstep was further reacted with a chloroform solution of silicontetraethoxide, 0.97 gram Si(C₂ H₅ O)₄ in 80 ml chloroform, under refluxfor 15 minutes. The atomic ratio of Si to total metal contaminants was0.5:1 . The solvent was removed by evaporation, the resulting catalystwas dried, calcined and an oxidative wash with an aqueous H₂ O₂, as inprevious examples, was finally applied. Metal removals and catalyticactivities were summarized in TABLE 3 as entries 3.a. and 3.b. forcatalysts obtained from the above two treatments.

                                      TABLE 3                                     __________________________________________________________________________     Passivation of Metal Poisoned FCC Catalyst                                   Feed Catalyst: Phillip's Borger Equilibrium Catalyst 002328                   Passivating Agent: (φO).sub.3 P + (EtO).sub.4 Si or SiO.sub.2                              % Metal     Cat. Activity                                    No.                                                                              Treating Conditions                                                                         Ni Fe V  Ce MA CPF                                                                              H.sub.2 /CH.sub.4                          __________________________________________________________________________      Contaminated Catalyst                                                                        0.33                                                                             0.72                                                                             0.71                                                                             0.10                                                                             59.1                                                                             3.02                                                                             20.20                                        a. Water washed Cat. (φO).sub.3 P                                         (1.5P/metal) dried and                                                        calcd at 1100° F., 4 hr.                                                              0.32                                                                             0.72                                                                             0.59                                                                             0.10                                                                             52.0                                                                             1.54                                                                             8.48                                         b. Colloidal silica (5wt%)                                                    on #43122 H.sub.2 O.sub.2 wash                                                followed.      0.30                                                                             0.71                                                                             0.48                                                                             0.10                                                                             65.1                                                                             0.73                                                                             5.47                                         (φO).sub.3 P(2P/metal) plus                                               (EtO).sub.4 Si(2Si/metal),                                                    dried and calcd at 1100° F.,                                           4 hr.          0.32                                                                             0.70                                                                             0.53                                                                             0.10                                                                             68.7                                                                             0.85                                                                             4.56                                                        (P: 0.69% on the catalyst)                                     a. Water washed Cat. (φO).sub.3 P                                         (0.5P/metal) dried, calcd,                                                    H.sub.2 O.sub.2 wash                                                                         0.33                                                                             0.72                                                                             0.51                                                                             0.10                                                                             70.2                                                                             1.04                                                                             5.16                                                        (P: 0.46% on the catalyst)                                   b. Further treat with                                                         Si(C.sub.2 H.sub.5 O).sub.4 (0.5 Si/metal)                                    dried, calcd and H.sub.2 O.sub.2 wash                                                          0.33                                                                             0.72                                                                             0.50                                                                             0.10                                                                             71.0                                                                             0.95                                                                             4.91                                       __________________________________________________________________________

The embodiments of this invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. In a process forconverting a hydrocarbon material having at least one metal contaminantselected from the group consisting of nickel, vanadium, iron and copperwhich comprises contacting the hydrocarbon material in a reaction zoneat hydrocarbon conversion conditions with a catalyst to form aconversion product and a deactivated catalyst having carbonaceousdeposits and containing at least a portion of said metal contaminant,and regenerating at least a portion of said deactivated catalyst torestore at least a portion of the catalyst activity by removing at leasta portion of said carbonaceous deposits to form a regenerated catalyst,the improvement which comprises: contacting at least a portion of saidregenerated catalyst with a liquid medium containing an effective amountof at least one silicon-containing material for passivating at least aportion of said at least one metal contaminant for a time sufficient topermit at least a portion of said silicon-containing material tointeract with said portion of said regenerated catalyst to form atreated catalyst containing silicon atoms from said silicon-containingmaterial, contacting at least a portion of said treated catalyst with anoxidative wash to form a washed catalyst, and transferring at least aportion of said washed catalyst to said reaction zone.
 2. The improvedprocess of claim 1 wherein the liquid medium is water substantially freefrom contaminating metals.
 3. The improved process of claim 1 whereinthe liquid medium is an organic medium capable of dissolving at least aportion of said at least one silicon-containing material.
 4. Theimproved process of claim 1 wherein said oxidative wash comprises aperoxide.
 5. The improved process of claim 4 wherein said peroxide ishydrogen peroxide which is present at a concentration in a range ofabout five to about fifty pounds of peroxide per ton of treated catalystcontacted.
 6. The improved process of claims 2 or 3 wherein the atomicratio of said silicon atoms from said at least one silicon-containingmaterial to total atoms from said metal contaminant contained in saidtreated catalyst is in the range of about 0.01:1 to about 3:1.
 7. Theimproved process of claims 2 or 3 wherein said effective amount of saidat least one silicon-containing material is such that an atomic ratio ofall silicon atoms in said liquid medium transferred to said treatedcatalyst to all atoms of said metal contaminants in said treatedcatalyst is in the range of about 0.01:1 to about 3:1.
 8. The improvedprocess of claims 2 or 3 wherein at least a portion of said treatedcatalyst is calcined prior to being transferred to said reaction zone.9. In the improved process of claim 1 wherein the effective amount ofsaid silicon, calculated as atomic silicon, in moles per liter of saidliquid medium is in the range of about 0.03 to about 1 when theconcentration of metal contaminants, calculated as its respectiveelement, in the deactivated catalyst is in the range of about 0.2% byweight to about 3.5% by weight, as based upon the total weight of thecatalyst.
 10. The improved process of claim 2 wherein said at least onesilicon-containing material is selected from the group consisting of:colloidal SiO₂ ; silanes having the general formula Si_(n) H_(2n+2)wherein n is an integer in the range of from 1 to 10; siloxanes havingthe general formula H₃ Si(OSiH₂)_(n) OSiH₃ wherein n is an integer inthe range of from 0 to 10; Si(Ac)₄ ; H₄ SiO₃ ; M₂ SiO₃ and M₄ SiO₄wherein M is a monovalent metal ion selected from the group consistingof group 1a of the Periodic Table of Elements.
 11. The improved processof claim 3 wherein said at least one silicon-containing material isselected from the group consisting of: colloidal SiO₂ ; silanes havingthe general formula Si_(n) H_(2n+2) wherein n is an integer in the rangefrom 1 to 10; siloxanes having the general formula H₃ Si(OSiH₂)_(n)OSiH₃ wherein n is an integer in the range of from 1 to 10; Si(A)₄wherein A is selected from the group of carboxylic acids containing upto four carbon atoms; a compound having a formula selected from thegroup consisting of: Si(OR)₄ and (RO)₃ SiOSi(R)₃ wherein each R isindividually selected from the group consisting of a hydrocarbylmaterial wherein the number of carbon atoms is in the range of from 1 to20, a halogen substituted hydrocarbyl material wherein at least onehydrogen of a hydrocarbyl material has been replaced by a halogenselected from the group consisting of fluorine, chlorine, bromine andiodine; a cyclosilane compound having a general formula (SiH₂)_(n)wherein n is an integer in the range 2 to 5; a cyclosiloxane compoundhaving a general formula (SiH₂.O)_(n) wherein n is an integer in therange of from 3 to 10; a silazane having a general formula H₃Si(NHSiH₂)nNHSiH₃ wherein n is an integer in the range of from 0 to 10;a cyclosilazane having a general formula (SiH₂.NH)_(n) wherein n is aninteger in the range of from 2 to 15; a compound having a generalformula selected from the group consisting: R_(n) SiH_(4-n), and R_(n)Si(OH)_(4-n) wherein n is an integer in the range of from 1 to 4 andwherein each R is individually selected from the group consisting of ahydrocarbyl material having up to 20 carbon atoms and a halogensubstituted hydrocarbyl material having up to 20 carbon atoms whereinsaid halogen is selected from the group consisting of fluorine,chlorine, bromine and iodine; a compound having a general formulaselected from the group consisting of: (RO)_(n) SiH_(4-n) and (RO)_(n)Si(OH)_(4-n) wherein each R is individually selected from the groupconsisting of a hydrocarbyl material having up to 20 carbon atoms and ahalogen substituted hydrocarbyl material having up to 20 carbon atomswherein said halogen is selected from the group consisting of fluorine,chlorine, bromine and iodine and wherein n is an integer in the range offrom 1 to 4; a compound having a general formula SiSX₂ wherein each X isindividually selected from the group consisting of bromine and chlorine;a hexahalodisiloxane having the general formula Si₂ OX₆ wherein each Xis individually selected from the group of halogens consisting offluorine, chlorine, bromine and iodine; and a compound having a formulaselected from the group consisting of: ((RO)₃ Si)₂ O, (R₃ Si)₂ O and(R.sub. 3 Si)₂ S wherein and each R of said compound is selected fromthe group consisting of hydrogen, a hydrocarbyl material having up to 5carbon atoms and a halogen substituted hydrocarbyl material having up to5 carbon atoms; a compound having the general formula ((RO)₃ Si)₂ Owherein each R is individually selected from the group consisting of ahydrocarbyl material having up to 5 carbon atoms and of a halogensubstituted hydrocarbyl materials having up to 5 carbon atoms; and acompound having a formula selected from the group consisting of (RO)_(n)Si(OH)_(4-n) and (R)_(n) Si(OH)_(4-n) wherein n is an integer in therange of 1 to 3 and wherein each R is individually selected froma groupconsisting of a hydrocarbyl material having up to 5 carbon atoms and ofa halogen substituted hydrocarbyl material having up to 5 carbon atoms.12. In a process for converting a hydrocarbon material having at leastone metal contaminant selected from the group consisting of nickel,vanadium, iron and copper which comprises contacting the hydrocarbonmaterial in a reaction zone at hydrocarbon conversion conditions with acatalyst to form a conversion product and a deactivated catalyst havingcarbonaceous deposits and containing at least a portion of said metalcontaminant, and regenerating at least a portion of said deactivatedcatalyst to restore at least a portion of the catalyst activity byremoving at least a portion of said carbonaceous deposits to form aregenerated catayst, the improvement which comprises: contacting atleast a portion of said regenerated catalyst with a liquid mediumcontaining an effective amount of a silicon-containing material, aphosphorus-containing material and an aluminum-containing material for atime sufficient to permit at least a portion of said silicon-containingmaterial, said phosphorus-containing and said aluminum-containingmaterial to interact with said portion of said regenerated catalyst toform a treated catalyst containing atoms of silicon, aluminum andphosphorus from said silicon-, aluminum-, and phosphorus-containingmaterial, respectively, and transferring at least a portion of saidtreated catalyst to said reaction zone.
 13. The improved process ofclaim 12 wherein the liquid medium is water substantially free fromcontaminating metals.
 14. The improved process of claim 12 wherein theliquid medium is an organic medium capable of dissolving at least aportion of said silicon-containing material and said material selectedfrom said group.
 15. The improved process of claims 13 or 14 wherein atleast a portion of said washed catalyst is calcined prior to beingtransferred to said reaction zone.
 16. In a process for converting ahydrocarbon material having at least one metal contaminant selected fromthe group consisting of nickel, vanadium, iron and copper whichcomprises contacting the hydrocarbon material in a reaction zone athydrocarbon conversion conditions with a catalyst to form a conversionproduct and a deactivated catalyst having carbonaceous deposits andcontaining at least a portion of said metal contaminant, andregenerating at least a portion of said deactivated catalyst to restoreat least a portion of the catalyst activity by removing at least aportion of said carbonaceous deposits to form a regenerated catalyst,the improvement which comprises: contacting at least a portion of saidregenerated catalyst with a liquid medium containing an effective amountof a silicon-containing material, a phosphorus-containing material andan aluminum-containing material for a time sufficient to permit at leasta portion of said silicon-containing material, saidphosphorus-containing and said aluminum-containing material to interactwith said portion of said regenerated catalyst to form a treatedcatalyst containing atoms of silicon, aluminum and phosphorus from saidsilicon-, aluminum-, and phosphorus-containing material, respectively,and transferring at least a portion of said treated catalyst to saidreaction zone.
 17. The improved process of claim 16 wherein saidoxidative wash comprises a peroxide.
 18. The improved process of claim17 wherein said peroxide is hydrogen peroxide which is present at aconcentration in a range of about five to about fifty pounds of peroxideper ton of treated catalyst contacted.
 19. The improved process ofclaims 12 or 16 wherein the ratio of all silicon atoms from saidsilicon-containing material to all atoms selected from a groupconsisting of phosphorus and aluminum, respectively, from saidphosphorus-containing material and said aluminum-containing material isin the range of about 0.1:1 to about 10:1.